A signal game model on security defense of information system

With the continuous development of informationization, the issues about information systems security have been plaguing firms. As the security of information systems level is uneven, this paper uses signal game theory to study how different types of firms to maximize their own safety benefits in the case of incomplete information. Then analyze necessary and sufficient condition for entirely successful detach Bayesian equilibrium, partly successful pooling Bayesian equilibrium, nearly failing mixed Bayesian equilibrium and corresponding strategies of firms. Finally we propose countermeasures to enhance the overall safety level of firms.